126results about How to "Adjustable molecular weight" patented technology

The invention relates to a preparation method of polypropylene wax. The method is characterized in that a liquid phase bulk polymerization technology is used, a supported metallocene catalyst is used, hydrogen is adopted as a molecular weight regulator, and a granular polypropylene wax product is directly obtained through catalyzing liquid propylene polymerization. The propylene polymerization reaction activity is not lower than 1000 times/h. The method has the characteristics of simple operation and high polymerization reaction activity, and the molecular weight of the polypropylene wax product obtained in the invention is adjustable and has narrow distribution.

The invention discloses pH response four-arm star block copolymer and a preparation method and application thereof. According to the copolymer, pentaerythritol is used as an inner core, each arm is connected with a hydrophobic group, a pH response group and a hydrophilic group; and the preparation method comprises the following steps of: performing ring opening polymerization on pentaerythritol to obtain hydrophobic group copolymer, performing acylation on the tail end of the hydrophobic group copolymer, and sequentially initiating pH response monomer and the hydrophilic group to perform electron transfer activating agent regeneration-atom transfer radical polymerization by using hydrophobic group copolymer of which the tail end is subjected to acylation and which is used as macroinitiator to obtain the pH response four-arm star block copolymer. The copolymer is self-assembled into nano micelle in an aqueous solution, so that insoluble medicines can be effectively solubilized; the copolymer is used for preparing a micelle medicine carrying system for insoluble anti-cancer medicines, and the medicines can be kept to be slowly released when pH of normal tissues is 7.4, and can be quickly released in a controllable way under the faintly acid condition that pH of cancer cells is 5 to 6; and the proportion of foundational groups of the copolymer is easy to control, and the copolymer is simple in synthesis process and high in yield.

The invention discloses a long-chain alkyl phenyl modified hydrogen containing silicone oil releasing agent preparation method. The method includes the steps of subjecting tetramethyl tetra-hydrogen cyclotetrasiloxane and a catalyst of chloroplatinic acid to reaction, dropping styrene for reaction for some time, dropping long-chain alpha-olefin and a chloroplatinic acid isopropyl propanol solution to obtain an intermediate product of tetramethyl alkyl phenyl cyclotetrasiloxane, subjecting the obtained intermediate product of tetramethyl alkyl phenyl cyclotetrasiloxane, octamethylcyclotetrasiloxane, hexamethyldisiloxane and an acid catalyst to full reaction, fully cooling the obtained liquid, slowly adding calcium hydroxide to adjusting the PH value to 6-7, filtering out solids produced in neutralization with a vacuum pump, adding anhydrous magnesium sulfate to adsorb water produced in neutralization, and filtering to obtain a long-chain alkyl phenyl modified hydrogen containing silicone oil releasing agent. The long-chain alkyl phenyl modified hydrogen containing silicone oil releasing agent prepared through the preparation method has the advantages of being simple in process, high in efficiency, low in cost, short in cycle and the like.

This invention relates to a photosensitive element for use as a flexographic printing plate and a process for preparing the plate from the element. The photosensitive element has at least one photopolymerizable elastomeric layer that comprises a binder, a monomer, a photoinitiator, an onium salt, and a leuco dye. Upon exposure to actinic radiation, the onium salt and leuco dye react resulting in a change of color in polymerized portions of the photopolymerizable layer. The color change provides enhanced image color contrast in the photosensitive element.

This invention relates to a preparation method of metal composite catalyst usd for olefinic polymerization. This metal composite catalyst includes : component I: a sort of Ti compound free of metal -PI bond; component II: one or more Ti at least containing one metal - PI bond, Zr, transition metal compound of V or Hf; component III: a sort of magnesium halide; component IV: : a sort of aluminium alkyl oxygen alkane or aluminium alkyl; component V: a sort of inside electron donor. This invention compound not homogeneous phase Ziegler - Natta catalyzer with metallocene catalyst component, not only be able to obtain polymer that has adjustable molecular weight at very widely extension and metabolic molecular weight distribution, furthermore may be able to may be able to adequate to production of adjustable polyolefine alloying, possess extensive application prospects.

The invention discloses a pH-responsive 6-arm star block copolymer and a preparation method and application thereof. In the structure of the copolymer, pentaerythritol is adopted as a kernel, and each arm is connected with a hydrophobic group, a pH-responsive group and a hydrophilic group. The preparation method comprises the steps of: carrying out ring opening polymerization of the pentaerythritol to obtain a hydrophobic group polymer, carrying out acylation of the end of the hydrophobic group polymer to prepare a macromolecular initiator, carrying out sequential initiation of regeneration of an electron transfer activator for a pH-responsive monomer and the hydrophilic group, i.e. radical polymerization for atom transfer, thereby obtaining the pH-responsive 6-arm star block copolymer. The polymer is self-assembled into nano micelles in aqueous solution, the dissolution of water-insoluble drugs can be enhanced effectively, the polymer can be applied in preparation of a micelle carrying system for water-insoluble anticancer drugs, and the drugs can be released slowly when the pH of normal tissues is 7.4 and rapidly in a controlled way under acidic conditions when the pH of tumor cells is 5-6; and the proportion of functional groups can be easily adjusted, the synthesis process is simple, and the yield is higher.

The invention discloses an ultrahigh-molecular-weight atactic polypropylene resin capable of being used for 3D printing, and a preparation method and an application thereof. The molecular weight of the ultrahigh-molecular-weight atactic polypropylene resin is 9*10<5>-5*10<6> g/mol, and the isotacticity (according to the percentage of a propylene unit isotactic sequence pentad [mmmm] in a polypropylene molecular chain) is 15-80%. The ultrahigh-molecular-weight atactic polypropylene resin is obtained by polymerization of propylene, the polymerized product is granular in shape, and the particle diameter is 50-1000 [mu]m. Because the resin has small and uniform particle morphology, the resin can be directly used as a raw material of 3D printing by adding a heat stabilizer, and is especially suitable for high-flexibility and high-ductility products molded by 3D printing.

The invention discloses a polycarboxylate superplasticizer with a mud preventing effect. The structural general formula of the polycarboxylate superplasticizer is as shown in the description, wherein R1 is H or CH3, R2 is H or COOM, R3 is an alkyl of C1 to C3, and M is H, Na, K or NH4. The invention also provides a preparation method of the polycarboxylate superplasticizer with the mud preventing effect. The superplasticizer synthesized by use of the process is applied to concrete within the aggregate mud content range of 0-8%, and a good application effect can be obtained through direct use without physical compounding.

The invention relates to a method for synthesizing polyaspartic acid by maleic anhydride and ammonia gas. The method comprises the following steps: performing substitution reaction of molten maleic anhydride and ammonia gas in a closed reactor and absorbing the residual gas after the completion of the substitution reaction; adding sodium hydrate solution into the reacted maleic anhydride and ammonia gas to perform neutrallzation reaction, so as to obtain a mixture of maleamic acid sodium and maleamic acid ammonium; directly heating the product in the closed reactor and performing condensation polymerization by stirring; steaming and drying the moisture after the completion of the condensation polymerization, so as to obtain the polysuccinimide solid; adding water in another reaction kettle and starting stirring; then adding the polysuccinimide solid into the reaction kettle and slowly adding sodium hydrate solution and heating to perform hydrolysis reaction, so as to obtain the polyaspartic acid solution. According to the method for synthesizing polyaspartic acid by maleic anhydride and ammonia gas, the production process is simplified and the polyaspartic acid prepared according to the method has a weight-average molecular weight of 2000-15000 and a molecular weight distribution index of 1.5-1.65, so that molecular weight requirements of various application domains are met and environment-friendly production process is realized.

The invention discloses a method for preparing a high polymer ultraviolet absorbent, which is characterized by the following: preparing the dilute solution by dissolving narrow distribution (D<1.2)high polymer by (reverse direction)atom transferring free radical polymerization(ATRP)with the good solvent; proceeding with reflux reaction with 2, 4-dihydroxy benzophenone (UV-0)low molecule ultraviolet absorbent with equimolar ratio in the accelerant function for 30-70 hours; preparing narrow distribution high polymer ultraviolet absorbent. Nuclear magnetism result show that the method make the grafting ratio of UV-0 low molecule ultraviolet absorbent which is grafted by PMMA reach 25.4%; the molecular weight of PMMA film without high polymer ultraviolet absorbent reduces 32.7% after the same molecular weight PMMA and PMMA which is grafted by UV-0 low molecule ultraviolet absorbent are aged 740 hours quickly by the ultraviolet light, the distribution of the molecular weight changes from 1.17 to 1.42; the molecular weight of PMMA film with 27% high polymer ultraviolet absorbent reduces 6.7%, the distribution of the molecular weight changes from 1.17 to 1.23, so the test result shows that high polymer ultraviolet absorbent prepared with the method can improve the ultra-violet resistance property of the high polymer material.

The invention discloses a high-efficiency decompression and augmented injection agent used for oil extraction. The high-efficiency decompression and augmented injection agent is characterized by comprising the following components in parts by weight: 1.0-2.0 parts of epoxy chloropropane, 1.0-2.5 parts of dimethylamine, 1.0-4.0 parts of trimethylamine, 0.01-0.1 part of ammonium persulphate, 0.015-0.15 part of sodium hydrogen sulphite, 0.01-0.2 part of ethanediamine and 0.02-0.06 part of triethylene tetramine. The invention also discloses a production method of the high-efficiency decompression and augmented injection agent. The production method is characterized by comprising the following steps of: adding epoxy chloropropane into a porcelain enamel reaction kettle; slowly feeding a mixed solution of dimethylamine and trimethylamine, prepared at room temperature in proportion; after feeding is completed, adding the ammonium persulphate, then adding the sodium hydrogen sulphite, and maintaining temperature in the kettle to be not higher than 5 DEG C; after feeding is completed, heating until the temperature in the kettle is increased to 60-90 DEG C, and reacting for 7-9 hours, so that an intermediate product is obtained; cooling the intermediate product to 40 DEG C, and slowly adding a mixed solution of ethanediamine and triethylene tetramine; and reacting again at the temperature of 40 DEG C, so that the high-efficiency decompression and augmented injection agent finished product is obtained.

The invention discloses a metal complex for efficient controllable ring opening of Epsilon-caprolactone, and specifically relates to thiourea metal salt. The metal complex is suitable for bulk polymerization and melt polymerization process of Epsilon-caprolactone and also suitable for slow controllable polymerization in a solution. The design of molecular weight of polycaprolactone is based on the ratio of a monomer to an initiator in the reaction system. The initiator is alcohol containing active hydroxyl terminal. The alcohol used as a co-initiator and the metal complex together have a synergistic effect on the catalysis system. The metal complex has rich selections of functional groups and is suitable for multiple polymerization conditions.

The invention discloses a method for preparing water-soluble graft polymers through active/controllable radical polymerization. The method can be used for controllable radical polymerization of various water-soluble monomers of a (methyl) acrylamide monomer, (methyl) acrylic acid, (methyl) acrylate and the like, so as to prepare the water-soluble graft polymers with different molecular weights. The preparation method is particularly realized through the following steps: firstly, preparing a water-soluble polyfunctional macroinitiator by adopting a chemical modification manner; secondly, initiating active/controllable radical polymerization of the water-soluble monomers by the macroinitiator under the heating or visible light/ultraviolet light irradiation condition, and preparing the molecular weight and chemical constitution controllable water-soluble graft polymers. The method is simple in synthetic route, low in production cost and safe and convenient to operate; the prepared macroinitiator is high in dissolution rate in water phase and high in initiating activity, and can be used for preparing the chemical constitution and molecular weight controllable water-soluble graft polymers.

The invention discloses a method for preparing a cation type hyperbranched ethylene or acrylamide polymer. The method comprises the following steps of: carrying out reversible addition-fragmentation transfer (RAFT) polymerization; and highly conversing in a polar solvent system by adopting a diene monomer and a chain transferring agent of the RAFT polymerization with low proportion through a semicontinuous operation process to prepare the cation type hyperbranched ethylene or acrylamide polymer. The polymerization process of the method is easily controlled, and molecular weights of a final product and distribution thereof can be controlled.

The invention relates to a block polymer dispersant synthesized by a reversible addition-fragmentation chain transfer (RAFT) technique. The prepared block polymer dispersant has adjustable molecular weight and narrow molecular weight distribution. Because the contained anchor groups (sulfo-group and amino group) can be easily adsorbed on the surfaces of glaze particles and exert a dispersion effect, and the water molecules adsorbed by hydration cations in the glaze slurry can be released, the viscosity of the glaze slurry is decreased, and thixotropy cannot occur easily. The invention also provides a preparation method of the block polymer dispersant synthesized by the RAFT technique. The synthesis of the dispersant by waterborne RAFT reagent component can realize industrialization, controllable molecular weight, controllable groups, and high dispersion efficiency. The block polymer dispersant synthesized by the RAFT technique can be used in coating, printing, energy, electronics, ceramics, pigment and filler, and commodity industries.

The invention discloses a photosensitive polyimide resin, a polyimide photocuring coating and a preparation method thereof. The structure of the photosensitive polyimide resin is as follows: a main chain structure contains a large number of alicyclic and benzene ring structures, and photosensitive groups are introduced at the tail end of the polyimide resin through benzene ring and carboxyl structures, so that the photosensitive polyimide resin is enabled to have good heat resistance and light sensitivity; and the main chain structure contains fluorine functional groups, so that the solubility of polyimide is improved, and the transparency and hydrophobicity of a polyimide photocuring coating are improved. The polyimide photocuring coating prepared by adopting an ultraviolet curing technology has photosensitivity, high transparency and good heat resistance, the light transmittance of the polyimide photocuring coating can reach 90%, and the polyimide photocuring coating can be widely applied to the fields of space flight and aviation, automobile industry and microelectronics.

A preparation method for temperature-sensitive core-shell structured microspheres and an application thereof in separation. According to the present invention, first mercaptopropyl triethoxysilane (MPT) and N-isopropyl acrylamide are reacted to generate semi-telechelic polymers, then the semi-telechelic polymers are coupled with ultrafine colloidal silica particles, so composite particles with poly-N-isopropyl acrylamide as the shells and colloidal silica particles as the cores are prepared. Differential scanning calorimetry tests show that the composite particles are temperature-sensitive. The prepared composite particles are used as a stationary phase in high pressure liquid chromatography, and water is used as a main ingredient of a mobile phase, and naphthalene derivatives are separated successfully through the control of column temperatures, achieving good separation effect.